Web Analytics

 Velocette - 600 type O
 Back to brands list

Velocette type O motocyclette motorrad motorcycle vintage classic classique scooter roller moto scooter
Photo ou archives : F-M. Dumas

Capacity : 600
Model : type O
Production : 1939 -
Category : (R) Street Bike


600 Model 0 -1939

Two crankshafts are better than one

In 1937, the works 350 KTT Velocettes were virtually invincible in racing, but their 500s were less brilliant, and the arrival of the blown multi-cylinders seemed to have written off these naturally-aspirated singles. So Velocette decided to break with tradition and began a bold project for a supercharged twin with two geared-together counter-rotating crankshafts - the legendary Roarer!

Two Projects for Marque Image

Velocette policy dictated that the marque's racers should resemble its production machines. In parallel with the Centric-blown Roarer developed by Harold Willis, the Brillant Australian engineer Phil Irving (formerly of Vincent-HRD) worked on the Model 0, designed to share the image of the Roarer, though its aims were totally different. The Model 0 was intended as an easy-to-use machine, easy to start, with good bottom-end

torque, exceptional flexibility and a power output of 30 hp.

Vibrations Eliminated

The two counter-rotating crankshafts practically eliminated vibrations and torque reaction. Another novel idea was the use of Metalastic flexible engine mounts. Moreover, the Type 0 offered adjustable swing arm rear suspension and shaft drive. In 1939, who could have asked for anything more? If it had reached the production stage, the Model 0 would have had virtually-square engine dimensions of 68x68.25mm, but the prototype used KTI pistons and rods. Sadly, the outbreak of war brought an end to the bold Model 0 project.


Engine: 58&c (74x68mm) air-cooled "doublesingle" with twin crankshafts; coil ignition

Power Rating: 30 hp @ 6000 rpm

Valves: overhead

Fuel System: carburetor

Transmission: 4-speed, shaft ftnal drive

Suspension: Webb girder forks (front); swing arm with twin adjustable dampers (rear)

Brakes: drum (front & rear)

Wheels: 19 inch interchangeable wire (front & rear)

Weight: 397 lb

Maximum Speed: 90 mph


Lack of finance forced the British industry to stay conventional, although the Velocette Model 0, one of the most sophisticated designs of its day, revealed its capacity for innovation.


Le fichier Moto Passion réalisé par François-Marie Dumas réunit près de deux mille photos accompagnées d'un historique très complet des machines présentées.
Il sera progressivement mis à jour ici et toute information complémentaire est la bienvenue sur info@moto-collection.org.

Cette documentation unique, qui constitue sans doute l'encyclopédie la plus exhaustive jamais écrite sur l'histoire de la moto, a été réalisée avec l'assistance de nombreux spécialistes dont principalement Didier Ganneau, Christophe Gaime, Mick Woollett, Jean Goyard, Bernard Salvat, Christian Rey, Yves Campion, Helmut Krackowizer, Michael Dregni, Michel Montange, etc. que je remercie ici.

Disponible sur demande :
- Les fiches originales sur papier
- Les photos et archives signées de mon nom en haute définition ou les documents originaux.
Me contacter sur info@moto-collection.org pour les conditions et droits d'utilisation.